The Fallout

Seven months later: Japan’s nuclear predicament.

A radiation detector in Iitate, where some of the heaviest concentrations of fallout were found. Once known as one of Japan’s most beautiful villages, it was given an official order to evacuate. Photograph by Kyoko Hamada.

On the afternoon of March 11th—a Friday—the Fukushima Daiichi Nuclear Power Station, on Japan’s Pacific coast, had more than six thousand workers inside. The plant, about a hundred and fifty miles north of Tokyo, is painted white and pale blue and is a labyrinth of boxy buildings and piping on a campus larger than the Pentagon’s. It has six reactors. Yusuke Tataki was in the concrete building that contains Reactor No. 4. He is a tobi worker—a scaffolder—and, at thirty-three, is small and nimble. Like many of the plant’s employees, he grew up nearby. He often skipped classes to surf, and after high school he worked, unhappily, on an assembly line welding circuit boards, until he got into scaffolding, which has kept him employed, on and off, at nuclear plants ever since. “Even when there’s no work elsewhere, there is work at the plants,” he told me recently.

At 2:46 P.M. on March 11th, an earthquake began to rattle the building, more violent than any Tataki could remember. It knocked him to the ground, and the lights failed. In darkness, he heard steel crashing against steel and men shouting. The building groaned. Heavy objects fell around him from heights of three or four stories. When the shaking stopped and emergency lights came on, the air was thick with a chalky haze of dust and concrete. Tataki knew that the only way out of the building was through an air lock—a set of parallel doors designed to prevent contamination—but the quake had jammed it shut. The workers around him were disciplined but anxious, and they banged on the door for help. “We all knew that during a quake everything in there could become contaminated with radiation,” he told me.

The quake had erupted beneath the ocean floor two hundred and thirty miles northeast of Tokyo, at a magnitude of 9.0—the strongest ever recorded in Japan. On that day, three of the Fukushima plant’s reactors were down for routine maintenance; the other three shut down automatically, as intended.

After a few minutes, a guard managed to open the jammed door, and Tataki hurried toward the parking lot. He has a wife and two children, and wanted to check on them and on his house. About seven hundred employees remained. “We had trained for this,” Keiichi Kakuta, a forty-two-year-old father of two, who worked in the public-affairs department, told me. “Of course, the mood was tense, but after someone said the reactors had shut down I saw the plant chief calmly instructing people what to do.” To ride out the aftershocks, Kakuta holed up, with most of the others, in the plant’s radiation-resistant Emergency Crisis Headquarters, situated on a small slope nearby. Japanese authorities had picked up the trail of a tsunami sweeping across the Pacific, but its precise approach was still a mystery.

In the imagination, tsunamis are a single towering wave, but often they arrive in a crescendo, which is a cruel fact. After the first wave, survivors in Japan ventured down to the water’s edge to survey who could be saved, only to be swept away by the second. In all, twenty thousand people died or disappeared along a stretch of the Japanese coast greater than the distance from New York to Providence.

At the plant, the first wave arrived at 3:27 P.M., but it did not overtop a thirty-three-foot concrete seawall. Eight minutes later, the second wave appeared: a churning white mass of water, four stories tall, that leaped over sixty thousand concrete blocks and barriers—designed to defend against typhoons, not tsunamis—and advanced toward the reactors. First, the water approached the turbine buildings, which had been built with large shutters facing the sea. It burst through the closed shutters and swamped the buildings. Inside, the plant’s emergency diesel generators, each the size of an eighteen-wheeler, were stored on the ground floor and in the basements. They were destroyed, and two workers who had been sent underground to check for leaks were killed. The water hurled pickup trucks pinwheeling end over end into delicate pipes and equipment, and it swamped the campus in roiling brown pools, fifteen feet deep, leaving the nuclear reactors protruding like boulders in a river. And then it recoiled into the sea.

Two minutes after the water arrived, the plant’s main control rooms began to lose electrical power. Hundreds of gauges and instruments went dark or froze. A worker who was keeping a log of the deteriorating situation scribbled something unprecedented in a Japanese nuclear plant: “SBO”—station blackout. Kakuta said to himself, “What happens now?” Without a constant source of coolant, the nuclear fuel rods in the heart of the three active reactors would eventually boil away the water that prevents them from melting down. The log entry was grim: “Water levels unknown.” Workers desperate for electricity had to improvise: they fanned out into the parking lot to scavenge car batteries from any vehicles that had survived the wave.

When the earthquake struck, the top ranks of Japan’s government were already in one place: at a meeting in a wood-panelled chamber of the national legislature, in Tokyo, discussing whether the Prime Minister, Naoto Kan, had taken illegal campaign donations. Kan was the fifth Prime Minister in four years; Japanese politics had become so fractious and unstable in recent times that when the German newspaper Die Zeit produced an illustration of Kan it mistakenly featured a Prime Minister who was booted from office two years earlier. Kan, a populist whose temper had earned him the nickname Irritable Kan, was sixty-four; his cabinet included younger officials, who conveyed an air of reform. At 7:03 P.M., Kan declared a nuclear emergency, and shortly afterward he ordered people within three kilometres of the plant to evacuate; the number of nuclear refugees eventually expanded to eighty thousand. But that evening Kan’s spokesman, Yukio Edano, projected calm: “Let me repeat that there is no radiation leak, nor will there be a leak.”

Gregory Jaczko, the chairman of the United States Nuclear Regulatory Commission, learned of the tsunami before dawn, in Washington, D.C., from his clock radio. The quake had struck overnight, D.C. time, and his first concern was about any tsunami effects on the West Coast of the United States. Once it was clear that there were none, he turned to Fukushima, but his staff was having a difficult time determining the details of what was happening. Over the phone, Japanese counterparts were vague or inconsistent, leaving exasperated American officials at the N.R.C.’s headquarters, in Rockville, Maryland, to watch the unfolding drama helplessly. “We were getting a lot of our information from the same source that everybody else was: open source, CNN, Japanese television,” Patricia Milligan, a senior N.R.C. emergency-preparedness specialist, recalled. Initially, Jaczko was not surprised; the tsunami had created an epic humanitarian crisis. He figured Japanese authorities were too busy to keep him updated. But gradually he reached a more disturbing conclusion. “It wasn’t a question of them not providing the information to us,” he told me. “The information just didn’t exist.”

The story of how Japan became one of the world’s most devoted, and improbable, advocates of nuclear technology begins in August, 1945. In the days immediately after the United States dropped atomic bombs on Hiroshima and Nagasaki, radiation was largely a mystery to the Japanese public; men and women had survived the explosion but were succumbing to a new illness—an “evil spirit,” as a national newspaper put it.

Nine years later, Japan had another encounter with nuclear technology: on March 1, 1954, the U.S. tested what was the world’s most powerful hydrogen bomb on Bikini Atoll, in the Pacific. The blast was more than twice the size that engineers had predicted, and a shower of radioactive ash reached far enough to envelop a voyaging Japanese tuna boat named the Lucky Dragon No. 5. The twenty-three crew members had no idea what had dusted them—“I took a lick; it was gritty but had no taste,” one wrote later—but by the time they returned to shore they were burned, blistered, and in the early stages of acute radiation sickness. Their contaminated tuna was sold at the market before anyone stopped it.

The ordeal caused a panic in Japan; a petition against further hydrogen-bomb tests secured the signature of one in every three citizens. It was the start of what became known as Japan’s “nuclear allergy.” In less than a year, Japanese filmmakers had released “Godzilla,” about a creature mutated by American atomic weapons. “Mankind had created the Bomb,” the film’s producer, Tomoyuki Tanaka, said of his monster, “and now nature was going to take revenge.” Godzilla’s radioactive breath and low-budget special effects were campy to the rest of the world but not to the Japanese, who watched the film in silence and left theatres in tears.

As the Cold War progressed, President Eisenhower fretted that the nuclear allergy could drive Japan out of America’s embrace. Ever since the Lucky Dragon incident, America had been portrayed as a nation of “skunks, saber-rattlers, and warmongers,” he complained in a meeting with the National Security Council. In a secret memo, the Acting Secretary of State told him, “The Japanese are pathologically sensitive about nuclear weapons. They feel they are the chosen victims.” He advised the President to apologize and compensate the fishing crew, but added that the best remedy for the Japanese people’s “emotion and ignorance” about the atomic age was to pull them into it—by building them a reactor. Eisenhower had recently announced the Atoms for Peace plan, to spread civilian nuclear technology to allies around the world. Representative Sidney Yates, of Illinois, proposed that an ideal place for Japan’s first plant would be Hiroshima itself—to “make the atom an instrument for kilowatts rather than killing.”

As it turned out, America’s emerging priorities coincided with Japan’s. After the Japanese surrender, in 1945, General Tomoyuki Yamashita was asked why his country had lost the war. He answered, “Science.” The triumph of American weaponry had convinced a generation of Japanese élites that their country must reëngage the world on the basis of trade and technology. But Japan’s islands were chronically short of coal and oil—the war had been partly a hunt for energy—and, as the country embarked on its economic growth spurt, it was desperate for new sources of electricity.

Nobody in Japanese politics was more inspired by nuclear power than Yasuhiro Nakasone, a fiery young nationalist who later became Prime Minister. As a sailor, he had witnessed from a distance the detonation over Hiroshima. “I still remember the image of the white cloud,” he wrote in “Politics and Life,” a 1992 memoir. “That moment motivated me to think and act toward advancing the peaceful use of nuclear power.” Nakasone believed that if Japan did not participate in “the largest discovery of the twentieth century” then it would “forever be a fourth-rate nation.” He also believed that the initiative must “proceed secretly,” because “opposition from academia and the press would blow us out of the water.”

To help persuade the Japanese public, the Americans enlisted the services of the C.I.A. Its agents turned to Matsutaro Shoriki, who ran the popular daily Yomiuri and was a proponent of nuclear energy. Shoriki, later known as the father of Japanese baseball, was code-named Podam, and, according to declassified files at the U.S. National Archives, he agreed to use his position to advance the cause. His newspaper co-sponsored an exhibition on nuclear power and ran a cheery series of articles that began with the headline “FINALLY, THE SUN HAS BEEN CAPTURED.” By 1964, Japan had established Nuclear Power Day, to be celebrated every October. And three years later a leader of the ruling party said that it was time for the Japanese people to “outgrow the ‘nuclear allergy.’ ” Secretly, the Prime Minister also commissioned a study on whether Japan should develop nuclear weapons of its own. (The study found “no technical impediments” to nuclear weapons but concluded that weapons would be costly and overly alarming to the public and to neighboring countries.)

The government made it clear to economically struggling villages in the countryside that a nuclear power plant held the promise of a fortune in property taxes and subsidies. “We were told that it would make us the Tokyo of Fukushima,” Kazuyoshi Satoh, a civil servant from the little town of Naraha, recalled. “Every time I went back, there was a new façade on the city hall or a new gymnasium or a new community center.” In one town, a plant even came with a subsidy for diapers. Satoh eventually became an opponent of the nuclear industry, which put him at odds with some neighbors. “Critics of nuclear power were seen as heretics,” he said.

Fukushima, which means “fortunate island,” erected its first plant—the one struck by the tsunami—on the former site of a Second World War imperial air base. Then it built another, not far down the rocky coast. Locals referred to their new skyline as the Nuclear Ginza, after the posh neighborhood in Tokyo. In a town beside the Fukushima Daiichi plant, people erected a sign that declares “Nuclear Power Is the Energy of a Bright Tomorrow.”

As night fell on March 11th, it became clear that the Fukushima Daiichi plant’s operator, the Tokyo Electric Power Company, which produces a third of the country’s electricity, had been unprepared for such a disaster. After the lights went out in the plant, engineers had to borrow flashlights from nearby homes in order to creep through dark, waterlogged passageways to study the gauges.

There was no mystery about what they were facing: the core of each operating reactor held at least twenty-five thousand twelve-foot fuel rods—slender metal tubes filled with pellets of enriched uranium. When things were working normally, the nuclear reaction in the core produced enormous amounts of heat, used to boil water for steam. The steam drove a set of turbines that generated electricity. The reaction also produced radioactive isotopes, which are safely contained within a series of steel-and-concrete defenses arranged like nesting dolls. But, with the power out, and emergency systems down, there was no way to cool the hot fuel; it was rapidly boiling away the water around it—creating huge pressure in the reactor—and eventually it would begin to melt, eating through the shells encasing it.

In a log later filed with the International Atomic Energy Agency, workers recorded frantic efforts to get water on the fuel. They tried to use a fire truck, but waves had thrown a storage tank across the road, making it impassable. To restore electricity, they called for emergency power vehicles, but those were stymied by traffic on damaged roads. In the dark, even familiar parts of the plant became perilous, because the tsunami had blown out the manhole covers.

Of the six reactors, No. 1 needed the most urgent help: the uranium was melting through the fuel rods, and when the damaged rods mixed with steam they gave off hydrogen, which is highly combustible. In order to prevent an explosion, the steam had to be released through a vent, and that meant piping radiation straight into the air. But the alternative was worse: wait too long, and an explosion would release a far larger burst of radiation. By 3 A.M., the government and Tokyo Electric knew that the vent had to be opened, but four hours later it was still closed. Later, the company said that it was waiting to make sure that all nearby residents had evacuated. Government officials have alleged that the company didn’t want to release radiation, because it would have immediately invited comparisons to the Chernobyl disaster, in the U.S.S.R., in 1986.

Finally, Prime Minister Kan flew by helicopter to the plant and demanded that Tokyo Electric open the vent. According to Yomiuri Shimbun, the chief of the plant replied, “We’ll form a suicide squad to do it.”

Opening the vent was such an unusual prospect that workers needed the blueprints to figure out how to do it, but the prints were in a building whose ceiling had collapsed. Only after they were retrieved did workers learn how the vent could be opened manually.

Six workers divided into three teams of two. Going in alone would be impossible, because the men would be operating in darkness, amid aftershocks, without radio contact with headquarters. According to the log, the teams would work in a relay, so that no one would be exposed to too much radiation.

The six workers assembled in the main control room. They had swallowed tablets that flooded their thyroid glands with iodine and hindered their bodies from absorbing radioactive iodine from the air; they wore dosimeters—portable radiation detectors that would warn them when they were nearing the legal limits of exposure. They were outfitted in heavy firefighting suits with oxygen tanks, gear that would shield them from inhaling and absorbing through their skin tiny particles that emit alpha and beta radiation, which can linger in the body for years, causing organ damage. The equipment, however, would provide little protection against gamma rays, so their only true defense would be to get out of danger as fast as possible.

At 9:04 A.M., the first two workers, carrying flashlights, set off into the darkness of Reactor Building No. 1. They found the manual gate valve, which can be opened by laboriously cranking a metal handle through hundreds of revolutions, like a man pumping an old-fashioned handcar down a railroad track. They cranked it open a quarter of the way and retreated. They had been inside for eleven minutes. The second team went in, but, with the vent partly ajar, the radiation level was climbing fast, and the men were driven back before they could even reach their target. They had been inside for no more than six minutes, but one of them received a radiation dose greater than the legal limits allowed for five years of work in the plant. It was deemed too risky to try again, and the third team was disbanded.

Despite those efforts, that afternoon, at 3:36 P.M., Reactor Building No. 1 exploded, hurling chunks of concrete that injured five workers and destroyed cables that had been laid in the hope of restoring electricity. With that explosion, the crisis passed an invisible line, as each problem triggered another. High radiation levels hampered workers trying to vent Reactor No. 3, and on the third day after the tsunami it, too, exploded. The following day, another blast occurred, this time at No. 4. On television screens throughout the world, three exposed steel carcasses were seen smoldering. An American aircraft carrier and its fleet left waters downwind of the plant after seventeen helicopter crew members returned from missions with traces of radiation.

By Tuesday, March 15th, conditions at the plant were becoming untenable. Radiation in part of the plant had climbed to four hundred millisieverts per hour; after less than thirty minutes of exposure at that level, the risk of cancer increases measurably. “It was the worst day of my life,” the Prime Minister’s nuclear adviser, Goshi Hosono, recalled to me. Japanese leaders, who had been working without sleep for days, were beginning to buckle under the demands. One suspected that he was having a stroke. Prime Minister Kan’s thoughts veered toward the apocalyptic. He imagined “deserted scenes of Tokyo without a single man,” he later told a Japanese reporter. The prospect of vast contamination in a country where land is already scarce struck him as a dire threat; to his mind, “Japan was facing the possibility of a collapse.”

In Washington, American officials watched the explosions on television with alarm, but a more subtle signal was also distressing: just after dawn on Tuesday, plant workers heard a boom near the suppression chamber of Reactor No. 2—a giant doughnut-shaped pool that absorbs steam from the fuel core. After the boom, pressure in the chamber sank to zero. To Gregory Jaczko, at the N.R.C., it was a chilling sight. “You pop the balloon, you lose the pressure,” he said. “That was the moment at which we registered that this was definitely going to be something very, very significant.” He and his colleagues at the N.R.C. suspected that the fuel was not simply melting down; the concrete-and-steel container, a vital line of defense, was now giving way, releasing a surge of radioactive gas and water—something that had never happened in America. (At Three Mile Island, fuel melted down but didn’t escape the reactor.)

A few hours later, the Japanese government heightened its advisory to the public, but only slightly. N.R.C. officials watched the news on a flat-screen television in the fourth-floor operations center. Based on their view of the events unfolding, they were surprised that the order was not broader.

By then, there was another problem: that morning, a fire had broken out around the spent-fuel pool on a floor above Reactor No. 4. It was a swimming-pool-like container where discarded radioactive uranium was held for storage. Each of the six reactors had a similar pool, an arrangement that had made it easy to load and unload fuel in normal conditions but now left the spent fuel acutely vulnerable to explosions and fires. To many experts, the pools posed an even greater potential threat than the reactors, because the pools were loaded with years’ worth of uranium and not encased on all sides in steel or concrete; they relied only on water to prevent them from overheating and spreading radiation. The timing was especially bad, because Reactor No. 4 had been down for maintenance at the time of the quake, so its nearly fresh fuel rods—more than thirteen thousand of them—were in the pool.

Chairman Jaczko was invited to testify on Capitol Hill the next day, and told lawmakers that the N.R.C. believed the pool had run dry. It was a striking claim, because it intensified the prospect of a far larger catastrophe—by one estimate, a worker standing beside a single dry pool could receive a fatal dose in sixteen seconds. It also raised questions about virtually identical pools at nuclear plants across the United States. (In June, the N.R.C. reversed itself and said that the Fukushima pools never ran completely dry, though it stands by the belief that the pools posed a grave threat.)

Experts at the Departments of State and Defense were trying to anticipate what would happen next; the possibilities were extraordinarily dangerous, including one that became known as “the popcorn scenario.” If there was another explosion, the spike in radiation could prevent workers from being able to continue injecting water onto the fuel cores. Then “one will pop and then another one and then another one and then another,” a senior U.S. official told me. Fuel that had already melted into a heap at the bottom of the reactor could melt through the steel pressure vessel and react with the concrete below, releasing vapors carrying highly radioactive materials such as strontium and technetium. In that case, “the environmental impact from that many reactors is hundreds of kilometres,” Charles Casto, the top N.R.C. official on the ground in Japan, said. “That was the scenario we were working, and there were a lot of people who believed in that scenario.” He himself had been skeptical that it would come to that.

“Hundreds of kilometres” meant that the impact could reach the outskirts of Tokyo, the world’s largest metropolitan area, with a population of thirty-five million. The Japanese government publicly maintained that the risk was manageable, but U.S. authorities were far less sanguine. Kevin Maher, one of the senior State Department officials on the interagency task force responding to the crisis, told me that by March 15th representatives from the State Department, the Defense Department, and other agencies were actively debating how to evacuate all American citizens from Tokyo—as many as a hundred thousand people. It would be an extreme maneuver. Maher, who retired from the State Department in April, recalled the debate: “Would you have to advise people to try to evacuate, running the risk that they could get stuck in the middle of the road with nowhere to shelter? Or would you advise people to shelter in place, meaning cover your windows or try to go into a basement?” Though they gave no public indications that the discussion was under way—it could have started a panic—they talked about the use of trains and commercial aircraft. Tokyo already had a gasoline shortage, and an evacuation on that scale would also have harmed relations with the government. No matter how they looked at it, Maher said, the prospect was “a nightmare.”

There are four hundred and thirty-two nuclear power plants around the world. The closest America has come to a disaster was a partial meltdown at the Three Mile Island plant, near Middletown, Pennsylvania, in 1979. It did not produce any deaths or public-health problems, but it chilled the advance of nuclear power in America: a series of “No Nukes” concerts, led by Bonnie Raitt and others, helped galvanize opposition, and since Three Mile Island no new projects have been planned.

A big accident becomes a laboratory for studying how to prevent the next one. When Charles Perrow, a Yale sociologist, studied the events at Three Mile Island, he discovered that problems had accelerated beyond what even skilled operators could handle: pumps failed, because of a maintenance error; a warning light was hidden behind a dangling paper repair tag. In all, four safety systems failed within thirteen seconds. Perrow observed that, as technological systems become ever more complex, disasters that appear to result from a confluence of bad coincidences become, in fact, unavoidable, as a failure in one part causes a failure in another and another in ways that no designer could predict. Extraordinary disasters become, in Perrow’s words, “inevitable.” He called these collapses “normal accidents.”

The normal-accidents theory, which is now used to assess risk in fields ranging from genetic engineering to the banking system, explained one reason that nuclear plants melt down, but it took another incident to illuminate just how much the effects depend on the characteristics of the societies involved. On April 26, 1986, a power surge triggered an explosion at Reactor No. 4 in Chernobyl, in what is now Ukraine. Soviet propagandists used to say their reactors were so safe that “we could build one on Red Square,” but the design turned out to be surpassingly bad: Reactor No. 4 had no containment system to stop the spread of radiation, and when it caught fire the graphite core burned like charcoal for ten days, lofting radioactive material into the atmosphere, where it was carried as far as Ireland. The Soviets said nothing about the accident; it was discovered only when the plume tripped radiation alarms at a nuclear plant north of Stockholm.

Local firefighters and first responders were dispatched with no special instructions. “They went off just as they were, in their shirtsleeves,” a fireman’s widow later told the journalist Svetlana Alexievich. They walked among shards of radioactive fuel and graphite. (A hundred and thirty-four developed acute radiation sickness. Twenty-eight men died within months and were buried in foil-lined coffins, beneath lead covers.) The nearly fifty thousand residents of the town of Pripyat, less than two miles away, were told nothing until more than twenty-four hours after the explosion, when they were ordered to evacuate temporarily and leave their possessions behind. Most never returned.

Soviet authorities failed to warn people to protect themselves. Cows ate tainted grass, and children drank the milk, contaminating their thyroid glands with radioactive iodine. Local doctors were barred from mentioning the meltdown in their diagnoses, to prevent “radiophobia”—unhealthy fear of radiation. The greatest long-term impact has been an epidemic of thyroid cancer, mostly among children who drank the milk. Five thousand cases have been discovered, but most are treatable; so far, approximately ten people have died.

According to the World Health Organization, Chernobyl will eventually have shortened the lives of four thousand people. A fifth of the farmland in Belarus was rendered unusable, and still accounts for seven hundred million dollars in losses each year. After the fire was put out, six hundred thousand workers were summoned from the corners of the Soviet empire to encase the remains in a concrete-and-steel “sarcophagus”; today, an area of the countryside within a thirty-kilometre radius of the plant is off limits and is known officially as the Exclusion Zone. It has become a nature sanctuary of sorts, home to wild boars and eagles and bears, and to pine trees that grow like bushes and other such mutations. Parts of the inner, most severely contaminated ring—the area within a radius of ten kilometres, known as the Ten—are expected to be uninhabitable for at least a hundred and fifty years.

After Chernobyl, many countries suspended plans to expand nuclear power, but Japan did not. Within two years, it had begun construction on five more plants. Although public opinion soured, the industry responded with a major investment in the visitors’ centers attached to its plants, adding swimming pools, golf courses, tennis courts, gardens, and IMAX theatres. One plant in Fukushima decorated itself with replicas of the homes of Marie Curie and Albert Einstein. Where the centers once targeted men interested in science, they now focussed on attracting women and children, according to Noriya Sumihara, a cultural anthropologist at Tenri University, who studied the phenomenon. “The companies believed that mothers were key decision-makers in the family,” he said. “If women felt the plants were relatively safe, then men would, too.”

Not far from Tokyo, the Tokaimura nuclear power plant maintains a complex called Atom World, which has two floors of games and interactive exhibits. When I visited recently, kids were being greeted by a young woman in a red apron printed with the image of a smiling uranium atom. There was a cluster of children playing a ring-toss game that had targets for different points along the nuclear-fuel cycle: radioactive waste for one ring, plutonium for another. Exhibits were narrated by cartoon characters, such as Uranium Boy and Little Pluto Boy, short for plutonium, who dispensed advice. “No need to worry too much!” he said on a poster about food with legal traces of radiation. When Japan was debating the use of a plutonium-fuelled reactor, in 1993, visitor centers added a video of Little Pluto Boy helping a child drink liquid plutonium, assuring him, “It’s unthinkable that I could cause any effects on the human body!” The video is no longer used. (It’s still available on YouTube.)

The visitors’ center at Tokaimura showed a short film that described uranium as “a gift from God” and “the fire of hope in the twenty-first century.” It did not mention the most famous event that had occurred in the town: the day, in September, 1999, when undertrained plant workers mishandled enriched uranium, causing Japan’s worst nuclear accident before Fukushima. Two of the workers died of organ failure brought about by acute radiation sickness, and more than four hundred people were exposed. Six power-company employees were prosecuted for professional negligence and violating nuclear-safety laws.

After Chernobyl, Japan’s declarations about the safety of its plants only seemed to grow more emphatic. Sumihara, who has interviewed power-company employees, said, “They’d say, ‘The structure of Chernobyl was totally different, and in Japan there are five layers of fail-safe measures. The Japanese standards for safety are a leader in the world.’ ” They came to regard even reasonable questions about safety as an existential threat. “They felt that if they said it was even slightly less than a hundred-per-cent safe, then that would introduce anxiety.”

The myth of total safety went beyond public relations and degraded the industry’s technical competence. According to Taro Kono, a legislator in the Liberal Democratic Party, emergency drills in the plants were scheduled to fit within an eight-hour workday, rather than simulating realistic conditions. A 2002 report by Tokyo Electric and five other companies declared, “There is no need to take a hydrogen explosion into consideration,” the Yomiuri Shimbun reported. (After the third hydrogen explosion at Fukushima, a company official conceded to the paper that “we were overly confident.”) Government regulators adopted a similar posture. A 1990 set of Nuclear Safety Commission guidelines announced, “We do not need to take into account the danger of a long-term power severance.” Even basic precautions were declared obsolete: Japan once developed a set of radiation-resistant robots to use in the event of a nuclear accident; in 2006, all but two of them were donated to a university and a museum. After the Fukushima meltdowns, Japan had to depend on devices from iRobot, an American manufacturer best known for producing the Roomba vacuum cleaner.

Over the years, nuclear regulators became so submissive to the industry that critics named the alliance Japan’s “nuclear village.” To some extent, Taro Kono blamed the fact that the agency charged with policing power plants—the Nuclear and Industrial Safety Agency—was part of the very ministry in charge of promoting them. “There’s no reason for you to regulate something, because when you go back to the ministry everyone’s going to be mad at you,” he said. Moreover, staff members are reluctant to change rules laid out by predecessors. As Kono put it, “Even after top bureaucrats retire, they have influence on personnel changes, so you have to have a good relationship with the old guys.”

Japanese nuclear regulators, like their American counterparts, have frequently been criticized for following a revolving door into lucrative jobs in the industries they police, and vice versa. Moreover, power-company executives are some of Japan’s most generous political donors; the utilities have not made corporate donations in a generation, but in 2009 individual executives gave seventy-two per cent of all personal contributions to the Liberal Democratic Party. In the late nineteen-nineties, a Tokyo Electric vice-president named Tokio Kano left the company to run, successfully, for parliament, where he led an effort to prevent the adoption of new textbooks until the Education Ministry removed references to the anti-nuclear movement in Europe. After leaving parliament, he returned to Tokyo Electric as an adviser.

Nuclear-safety scandals began to emerge. In June, 2002, Tokyo Electric was forced to reveal that for two decades it had faked hundreds of repair records, at the Fukushima Daiichi plant and at several other reactors. Five years later, it conceded that it had lied in its previous acknowledgment of lying and owned up to six more emergencies at Fukushima Daiichi that had been concealed. The gravest error, perhaps, was underestimating the risk of tsunamis. The Nuclear Safety Commission’s official guidelines declared that, in the event of a big wave, “safety functions of facilities shall not be significantly affected.” But experts inside and outside the government had warned authorities about new research on the speed of meltdowns in the event of a power loss and the acute threat posed by storing diesel generators in a basement.

Of all the warnings that were ignored, the most significant was from the past. On June 24, 2009, two senior Japanese seismologists appeared before a government-led safety panel to warn that the Fukushima Daiichi plant was acutely vulnerable to tsunamis. They pointed to the words of ancient historians who described a wave in the year 869 so large that it left “no time to get into boats or climb the mountains”; it devastated a castle and left “everything utterly destroyed.” According to a transcript of the hearing, a Tokyo Electric official responded that “future research should evaluate” the claim, because it appeared that “there isn’t much evidence of damage.” The plant was designed to absorb swells of up to about nineteen feet in height; the tsunami that arrived in March was more than twice that tall.

By March 15th, the fourth day after the meltdown began, the radiation levels in the main control room of Reactor No. 2 were so high that workers once again had to rotate in and out. It was clear that in the process of bringing the plant under control some people would receive doses previously considered illegal. Normally, Japanese workers were barred from receiving more than a hundred millisieverts over five years; now the Health Ministry officially raised that limit to two hundred and fifty millisieverts—five times the maximum exposure permitted for American workers. “It would be unthinkable to raise it further than that,” the Health Minister, Yoko Komiyama, said at a news conference.

Members of Japan’s defense forces arrived the next day. The results were not reassuring. Chinook helicopters scooped up buckets of seawater from the Pacific and nosed in toward Reactor No. 3, but they were forced back by high radiation. Lead plates were bolted to the bellies of the choppers for a second attempt, the next morning, but most of the water scattered in the wind. By evening, military fire engines had arrived, equipped with steel cladding and high-pressure hoses designed for jet-fuel fires. Water arced into the mangled remains, and steam poured out of Reactor No. 3.

A more decisive maneuver had been gathering strength, with far less attention, for several days. Even as buildings exploded, some of the workers had hooked up a train of fire trucks capable of generating enough pressure to inject water directly into the fuel cores. (As with the helicopters, they drew water from the ocean—a desperate measure, because a multibillion-dollar reactor that has been bathed in saltwater can never be used again.) The drenching continued around the clock, and it went on for months—an approach known as “feed and bleed.” Casto, of the N.R.C., said, “No one ever envisioned steam-cooling reactors for long periods of time. In reactor world, this is all new.” The process was ungainly, and it produced millions of gallons of radioactive water that is dangerous to store, but it probably did more than any other measure to avert a far worse disaster.

By the afternoon of March 16th, American officials had their first glimmer of decent news. To predict where a plume of radiation is likely to go, the N.R.C. uses a computer program called RASCAL, which weighs factors such as the quantity of radioactive material, the weather, and topography. When the model was released, that afternoon, it showed virtually no danger beyond fifty miles from the plant. “There was relief in the sense that, O.K., we don’t have to evacuate Tokyo,” Maher, of the State Department, said. The results still called for a dramatic step: Japanese authorities had ordered people within eighteen miles to evacuate or to stay indoors, but now the State Department warned U.S. citizens to stay at least fifty miles from the plant and to defer travel to Japan. It was the first time that American nuclear regulators had so publicly contradicted their counterparts in an allied country. Some U.S. and Japanese critics complained that the U.S. call for evacuation was excessive and sowed panic; those who fled came to be called “fly-jin,” a play on gaijin, the Japanese word for foreigner. The U.S. stands by the warning, which remained in effect for more than five months.

After the pressure drop that so alarmed observers in Washington, Tokyo Electric temporarily pulled out most of its workers. Six hundred and fifty were sent away, leaving several dozen in the headquarters building. Reporters named them “the Fukushima 50.” They were actually seventy and, by the next day, after more workers returned, about three hundred, but the name stuck, and the concept earned instant fame abroad, where it fit comfortably into clichés about Japan. The Chicago Sun-Times called them “human sacrifices”; British tabloids hailed the “nuclear samurai.” A Facebook page popped up to suggest they be awarded the Nobel Peace Prize. People saw in the Fukushima 50 what they wanted—“the exact opposite of the Wall Street bankers,” a blog commentator wrote. “Their nation will love them,” another wrote.

But in Japan the reaction was noticeably different. The Japanese press praised the workers’ bravery and sacrifice, but it generally avoided discussion of the Fukushima 50; Asahi Shimbun suggested that “Fukushima 700” would be more accurate. In the Japanese edition of Newsweek, Takashi Yokota and Toshihiro Yamada wrote that, in the emphasis on the workers, the “predicament of the victims has been made secondary.” But Japan’s unease about the nuclear workers ran deeper than not wanting to distract from the suffering left by the tsunami: the workers were symbols not only of the failure to curb the abuses in the nuclear industry but also of an expanding underclass in a nation where ninety per cent of the public once identified itself as middle class. Years before the tsunami, labor activists had drawn attention to the dangers facing “nuclear gypsies,” the low-level workers who roamed from reactor to reactor looking for work. At the time of the tsunami, some of the workers at the Fukushima plant were earning the yen equivalent of eleven dollars an hour—the same as part-time help at McDonald’s in Tokyo.

After the tsunami, Tokyo Electric barred rank-and-file employees from speaking publicly, and the ban is still in effect. The closest the Japanese public has come to hearing about workers’ experiences was during an appearance by three firefighters at a press conference on March 19th. “I sent my wife a message that I was going to Fukushima’s nuclear power plant,” Yasuo Sato, a commander of the Tokyo Fire Department’s Hyper Rescue Squad, said. “She replied with a one-line sentence: ‘Be Japan’s savior.’ ”

Over the summer, I met now and then with a worker at the plant who had returned shortly after the meltdowns. He had no illusions about why his country was uneasy with his assignment. “The company caused all these problems, so of course it will have to send people to solve them,” he said. “It’s something to be ashamed of.” He was boyish and animated, an amateur military buff, and he was resigned to the risks associated with his work. When he arrived, workers were still sleeping on the floor, subsisting on canned rations, crackers, juice, and instant rice. By late summer, the food had improved, but extraordinarily dangerous hot spots remained at the plant, including a pipe that was giving off ten sieverts of radiation per hour—enough to deliver a fatal dose in less than thirty minutes.

This man had once enjoyed his work at the plant. In the West, he would have been called a “jumper”—a nuclear worker willing to jump in and jump out of high-dose conditions. Such workers are also known as dose fodder, glow boys, and gamma sponges. But this man’s enthusiasm had diminished. He had grown up with a view of the plant from his bedroom window, and now his house had been evacuated. “At Chernobyl, you know, the workers received medals,” he said one evening. “We’ll be lucky if we get a commemorative towel or a ballpoint pen. We are taboo.”

The bus from Tokyo to the center of Fukushima takes three hours and passes through a string of tunnels that divide the skyscrapers of the capital from the forested hills of the northeast. Much of Fukushima Prefecture—population two million—has the feel of Maine: organic farms, pine forests, coastal towns where the air is spiked with sea salt. Every year, it awards the title of Miss Peach to advertise the sweetness of Fukushima fruit.

At the end of May, when I visited Yusuke Tataki, the worker who was inside Reactor Building No. 4 at the time of the quake, he said that he had passed up offers to go back as a jumper. He lives in a suburban stretch of undulating, bamboo-filled hills twenty-five miles from the plant, and he was worried about what the meltdowns might mean for the future of Fukushima. “I know how bad an accident is,” he said, pulling out a cigarette, as we sat in a small tatami-mat living room in his house. Three days after the quake—when buildings were still exploding at the plant—Tataki loaded up his family and drove them away. They returned, two weeks later, only because school was starting. “If we didn’t have the house, we would leave and not come back,” Tataki said. “But I have a mortgage, and who’s going to buy a place in Fukushima now?” Relocating posed its own fears; the rumor around town was that being from Fukushima might become a stigma, just as being from Hiroshima was for survivors of the atomic bomb. “If we go to Tokyo and our kids have accents, other children will figure out right away where they’re from.” His mood darkened. He said, “The government won’t tell people to evacuate, because then it would have to compensate everyone.”

That kind of distrust was astonishingly pervasive; a poll in late May showed that more than eighty per cent of the population did not believe the government’s information about the nuclear crisis. That explains why, even long after the evacuation maps were clear and widely known, people in places that had been officially declared safe, like Tataki’s home town of Iwaki, were divided. “People are arguing at their dinner tables: Should we go; should we stay?” said Sayoko Ishihara, a seventy-eight-year-old woman I met one afternoon across from a Mr. Donut shop.

Even Fukushima’s unharmed areas are confronting—to put it mildly—a branding problem. “Yes, I’m afraid the whole world knows this name now,” Professor Shuji Shimizu, of Fukushima University, told me when I visited him at the university’s campus, which is arrayed across a tranquil slope on the edge of Fukushima City. Shimizu is tall and thin, and he walked me outside to show off a freshly laid parking lot, beneath which the school had buried tons of contaminated leaves and branches, in the hope of reassuring potential applicants that the campus is safe. “We have a hundred and fifty foreign students this year,” he said. “But somehow I suspect next year we will have zero.”

The local newspaper was running charts of radiation readings regularly, like the weather report. There was also a lot of bad information going around: in a sign of how far public confidence had sunk, people were invoking the Soviet handling of Chernobyl as a standard to aspire to. When I visited a community center that was conducting free radiation checks of food and objects, people arrived with boxes of snow peas, turnips, eggs, and meat. A father whispered that he had secretly swiped a sample of swimming-pool water from his daughters’ school.

It was an oppressive combination of stresses: people were drowning in jargon—sieverts and becquerels and half-lives—at the very moment that they were trying to make decisions about their family’s health. Natsuko, a young mother, was among the parents who turned up at the community center. “If we stay here for one year, how much radiation would my son be exposed to?” she asked a social worker who was helping arrange relocations. Natsuko’s husband, a thickset office worker, was seated nearby; their two-year-old son, wearing a cowboy hat, cargo pants, and a tiny cotton facemask with cartoon cars printed on it, sat between them. “Well,” the social worker said, entering numbers into a calculator, “it comes to fourteen millisieverts. Even though the government is giving free checkups, that doesn’t mean you’ll be healthy. If I were the parent of a small child, I would be leaving right now.”

Natsuko’s shoulders slumped. “I didn’t evacuate in March, and I regret that. Is there anything I can do to make up for it?” she asked. Tears appeared on her cheeks. The boy looked at his mother, then his father, then the social worker, and then his mother again. His father scooped him up and they went for a walk. The social worker said, “It’s not too late. Even for two or three months, you should evacuate.”

Initially, public anger was fixed on Tokyo Electric. The families of senior executives were placed under police guard after their addresses were posted on a Web site critical of the company. But on a weekday afternoon in May protesters of a kind rarely seen in Japan turned up at the headquarters of the Ministry of Education, Culture, Sports, Science, and Technology, in Tokyo. They were parents and grandparents who had taken the bus from Fukushima. Their target was specific: in order to keep more schools open in Fukushima, the government had raised the limits on radiation exposure for the general public. Scientists said that the limits were safe, but people were unconvinced.

In front of the Ministry, a parent with a bullhorn began with a list of rules for the other protesters: “The demonstration will go from precisely one o’clock to two-thirty. When someone is speaking, please don’t interrupt.” Then the protesters began to shout. “Minister, come out! Minister, come out!” They carried signs, including one that said “Don’t Use the Children of Fukushima as Marmots.” (The marmot is Japan’s guinea pig.)

A low-level government official eventually came out to hear the group’s demands. Beside me on the edge of the crowd, a young protester, an actress named Hayuki Ishikawa, eyed him warily and said, “That doesn’t look like his real hair color. It’s too black. How can you trust someone if you can’t trust his hair?” It began to drizzle. She tugged a floral-patterned scarf up over her head and said, “This is black rain. It’s not safe.”

Later, one of the organizers, Seiichi Nakate, a fifty-year-old father of two, told me he feels that he himself bears some responsibility for what happened. “If you look back to the Second World War, we waged war against the world’s major power, and that was the wrong decision for humanity. After we lost the war, Japanese people became even more politically indifferent. It permeated the whole social structure.” He went on, “By nature, Fukushima people are very calm and quiet, but we are standing up. We endured through years with the nuclear plants, and now we have woken up.” The group prevailed; a week later, the government went back to the old radiation limits.

The Fukushima meltdowns scattered nuclear fallout over an area the size of Chicago. Government scientists estimate that the total radiation released on land was about a sixth of the level at Chernobyl. The government discovered stores selling beef, spinach, and other foodstuffs that contained small amounts of radiation, and it was racing to pull the products from shelves. Because of such measures, the health consequences of the meltdowns will likely be far smaller than the public imagines.

Unlike the Russians, Japanese authorities warned parents not to give local milk to their children. (Because their cells grow at a faster rate, children are especially vulnerable to thyroid damage.) So far, none of the workers at Fukushima have been exposed to doses high enough to cause acute radiation sickness, and scientists do not expect a large increase in cancer cases. An analysis published last month by the Princeton University physicist Frank von Hippel estimated that roughly a thousand deadly cancers may result from the Fukushima meltdowns; he cautioned that the data are preliminary and that psychological effects should be considered as well.

Dr. Fred A. Mettler, Jr., the American representative to a United Nations committee on radiation assessment, said, “Forty per cent of people in developed countries get cancer anyway, so, compared to that normal rate, I think the risk is going to be low—and may not be detectable.” Of nearly four thousand workers who have passed through the plant since the meltdowns, only a hundred and three have been found to have received more than a hundred millisieverts of radiation. At that level, scientists predict about a one-per-cent increase over the normal rate of cancer. The most serious cases are two workers who were exposed to more than five hundred millisieverts in the first weeks of the crisis.

It is more difficult to pinpoint the toll on the land. The impact of a nuclear accident depends, to an extraordinary degree, on luck—not only on the fateful actions of workers in a crisis but on the direction of the wind. For four days after the meltdown, the wind blew out to sea. But then it swung sharply around and turned to the northwest. To make matters worse, there was rain and snow, which captured radioactive particles in the air and drove them deep into Fukushima’s mountain forests and streams. For days, the government stayed silent about where the fallout was going. Leaders were “afraid of triggering a panic,” Goshi Hosono, the minister in charge of the crisis, has said. It was unwise; some evacuees fled into the plume, a mistake that has prompted one local mayor to accuse the government of murder.

When the government finally released a map of the fallout, it became clear that some of the heaviest concentrations were in the tiny village of Iitate (pop. 6,200), twenty-five miles northwest of the plant. Less than a year earlier, it had been named one of “Japan’s 100 Most Beautiful Villages.” It was given an official order to evacuate at the end of May. When I stopped by, on the day before the deadline, a traffic light was blinking without a soul around. At the village hall, where moving companies had taped their phone numbers to the windows, Vice-Mayor Shinichi Monma, born and reared in the town, was maintaining an air of crisp efficiency. “Unfortunately,” he said, “our residents were irradiated.”

When the oldest man in town—a hundred and two years old—heard the news, he killed himself, rather than flee, the papers reported. In front of the village hall, a machine that looked like an oversized parking meter flashed a real-time radiation reading in large red digits: 7.71 microsieverts . . . 8.12 . . . 7.57. Being there was equivalent to receiving a chest X-ray every twelve hours.

In addition to its beauty, Iitate was known for its beef. Now the villagers had to kill their cows—nearly three thousand of them. Nobody wanted to see pictures of them wandering, skinny and abandoned, like the animals in some other evacuated towns.

To guard against looters, the villagers had agreed to take turns patrolling in the months ahead. Village leaders were saying that they expected to return to their homes within two years. But the vice-mayor conceded to me, “There’s nothing to back that up; it’s just for the villagers’ morale. If people are told it will be more than two years, they might never come back.” The central government avoided making any predictions, but five months after the quake it acknowledged that areas within three kilometres of the plant will likely be uninhabitable for decades.

When I returned to Iitate two months after the evacuation, I was joined by Mari Kobayashi, an outgoing forty-six-year-old widow who owns a twelve-acre farm. She was originally from Nagoya, Japan’s third-largest city, and had a career in fashion before moving up to the woods with her husband, a linguist who gave up his job as a Russian translator to work with his hands. They raised free-range chickens and organic fruits and vegetables. “Romantic, huh?” she joked, as she steered her Toyota along empty roads. On her dashboard, she had a laminated sign issued by the village, which identified her to the patrols as a local. After each visit, she tucked it away, to avoid unwanted attention. “Everybody from here has scattered now,” she said. “When I run into a patrol, I ask about this person or that person.” Approaching her house, we passed a strangely beautiful sight: where rice fields should be, workers had planted acres of blazing yellow sunflowers, a species that can leach some of the radiation out of contaminated soil. The sunflower seeds had been sown in patches all over Fukushima, by people in protective white suits, and once the blooms faded they were to be bagged and buried like toxic waste. Japanese scientists later concluded that the sunflower campaign had little effect.

Kobayashi’s house was on a hillside, overlooking a lily pond and stands of mature cedar and pine. Bullfrogs belched in the creek. Inside, things were dusty but untouched: wool slippers in pairs; cat drawings on the kitchen walls; snapshots of Mari cracking up at a picnic table, her husband sleeping in the sun.

We walked out to the vegetable patch, which was wildly overgrown, with branches reaching out through the fence posts. At my feet, a beetle high-stepped through unmowed grass. Insect populations dwindled around Chernobyl in the years after the meltdown, and I wondered if that would happen here. For now, the bugs and animals had the run of the place. Kobayashi wore a broad sun hat and a long red skirt. She stood with her hands on her hips and surveyed the damage left by a wild boar run amok. “The boar ate what it needed,” she said. “If it was people, they would have taken everything, but nature takes only what it requires.”

Since the meltdowns, her relatives had pleaded with her to return to the city, but she had decided to stay in a borrowed house only forty minutes away. Her husband had died here, four years ago, and that made it especially hard for her to leave. “When he died, this forest saved me. My husband’s soul is in this land. I can’t abandon him.

“Some people have decided that nowhere in Fukushima is safe,” she went on. “I respect their decision, but I’m glad I didn’t escape too far. Radiation is frightening, but there is life beyond it. I won’t let it limit me. I won’t let a power plant take my life away.” She added, “It wasn’t just the Tokyo Electric Power Company that caused all this. It was all of us who lived with it and enjoyed the benefits.”

As the sun sank, we left the house and headed back by car across the darkened hills. We passed houses I’d seen on my previous visit, but now they were empty, with the shades drawn, and in the twilight they looked papery and ephemeral, as if they could slip back into the woods without anybody there to notice.

The March tsunami was history’s most expensive natural disaster, with losses estimated at three hundred billion dollars. But the Fukushima meltdowns, the world’s worst nuclear accident in twenty-five years, were man-made, the consequence of failures that laid bare how far Japan’s political and technological rigor have drifted from their apex. As Yoichi Funabashi, the former editor-in-chief of the Asahi Shimbun, put it, Fukushima shattered the “delusions of graceful decline.”

In a speech in June in Barcelona, the writer Haruki Murakami drew a blunter connection with history than others have ventured: “This is a historic experience for us Japanese: our second massive nuclear disaster. But this time no one dropped a bomb on us. We set the stage, we committed the crime with our own hands, we are destroying our own lands, and we are destroying our own lives.” He challenged his countrymen to acknowledge “the failure of our morals and our ethical standards.” He said, “While we are the victims, we are also the perpetrators. We must fix our eyes on this fact. If we fail to do so, we will inevitably repeat the same mistake again, somewhere else.”

The chastening was not confined to Japan. Germany resolved to phase out nuclear power by 2022; Austria, Italy, and Switzerland also reconsidered. In the United States, which is home to a hundred and four commercial reactors, critics noted that if a problem at the Indian Point plant, thirty-five miles north of Times Square, forced an evacuation of fifty miles—the same level imposed by the U.S. in Japan—it would encompass an area of nearly twenty million people. David Lochbaum, the director of the nuclear-safety project at the Union of Concerned Scientists and a former nuclear-plant engineer, told me, “Anybody who saw the first explosion at Fukushima knew that the status quo was dead.”

Although an initial inspection of U.S. reactors by the N.R.C. in May found no “imminent threat,” it concluded that at about a third of them some emergency equipment might be vulnerable to extreme circumstances, such as fires and explosions, in ways that are startlingly reminiscent of details at Fukushima. At one plant, a single, diesel-driven pump was incapable of providing emergency water to both of the reactors on site. At another, firefighting equipment is stored in a building not fortified to withstand an earthquake, because a severe fire and an earthquake “were not assumed to occur coincidentally,” according to the report.

Still, within months the American nuclear industry had regained its confidence. Its representatives endorsed some changes, including additional portable backup generators, but when an N.R.C. task force, created after Fukushima, recommended upgrading the “patchwork” of regulations that govern American plants, the Nuclear Energy Institute argued against making changes in haste. “It’s not that we’re not going to do it; let’s find out a little bit more about what happened, and then we can make the right decision and do it right once,” Adrian Heymer, the N.E.I.’s executive director for strategic programs, told me.

That debate became more urgent after August 23rd, when a 5.8-magnitude earthquake, whose epicenter was in Virginia—the largest quake in the area in more than a century—shook the East Coast. It affected twenty American nuclear reactors, most seriously the North Anna plant, in Virginia, where the ground shook with greater intensity than the plant was designed to withstand—the first time that has happened at an American nuclear power station. Concrete containers of spent fuel that weighed a hundred and seventeen tons shifted a few inches. Five days later, when Hurricane Irene struck the East Coast, emergency sirens failed to function properly at three nuclear plants, and at Indian Point a canal overflowed. On September 9th, N.R.C. staff people suggested ordering power plants to review their ability to survive quakes and floods “without unnecessary delay.”

On balance, the Fukushima disaster handed no easy victories to either side of the nuclear debate: defenders can no longer pretend to have engineered away the risks of generating a billion watts in a concrete building, and opponents cannot easily suggest that a meltdown will produce the huge number of immediate casualties that the public imagines. Even after Fukushima, several influential environmentalists have renewed their contention that nuclear power is an unavoidable part of weaning the planet from the burning of fossil fuels.

But, for a while, the Fukushima meltdowns have returned nuclear technology to its rightful place: a target for vigilance, scrutiny, and a healthy degree of fear. Looking back, it is easy to see where the Japanese nuclear system lost its footing: when the industry stopped seeing the risks; when decisions that affected millions of people were left up to desperate villages; when urbanites paid their electric bills without knowing where, exactly, the power came from. And yet, for all that went wrong before the meltdowns, the fundamentals of Japan’s open society served it well in the aftermath: elected officials ordered evacuations and alerted people not to drink tap water and suspended shipments of raw milk; parliament launched investigations into all that went wrong; and the Japanese press chronicled a raging national debate about the future.

The Japanese government ordered an initial round of stress tests—simulated disasters—for most of the nation’s nuclear reactors. It passed a tariff that promotes the use of renewable energy sources, which had withered during the heyday of the nuclear program. And, in an important legal change, it moved to separate the regulators in charge of policing the plants from the industrial ministry in charge of promoting them.

Not long after the meltdowns, Japan’s anti-nuclear activists were convinced that they had won the debate, and Prime Minister Kan made the dramatic gesture of calling for a temporary shutdown of a plant in central Japan where scientists have estimated that there is an eighty-seven-per-cent chance of a big quake. Many other plants closed for regular maintenance and have delayed reopening; by the end of the summer, fewer than a third of Japan’s fifty-four reactors were in active use. But soon factory owners were warning that power cuts would lead to a recession, and that argument prevailed. Prime Minister Kan, unsurprisingly, did not last long; on August 26th, he resigned, and his successor, Yoshihiko Noda, reversed course, prodding local communities to allow plants to re-start. By fall, a consensus had taken hold among Japanese politicians and intellectuals: there would not be a sudden end to nuclear power in Japan. The country would possibly close some of its oldest plants, but the rest—by one estimate, thirty-six of the fifty-four reactors—would endure.

Anything else would be “idealistic but very unrealistic,” the Economics Minister, Kaoru Yosano, told me when I saw him at his office not long before the new cabinet took over. Yosano was of the generation that triumphantly advocated nuclear power—he bitterly recalls growing up in a house with two light bulbs—and he does not hide his suspicion of what he describes as “so-called renewable energy.” He said, “Simple calculation tells us that our country is not big enough” to rely on solar and wind farms. He acknowledged the upheaval wrought by the Fukushima disaster, but he returned, at last, to a frank calculation: “Until this moment, no one died.”

He continued, “We thought that human beings—the Japanese—can control nuclear by our intelligence, by our reason. With this one accident, will that philosophy be discarded? I don’t think so.” He was quiet for a moment, and then he surprised me with a final note—one not of resolve but of caution, directed at “those countries that are just now planning to go into the nuclear age.” He said, “China will build a hundred or two hundred nuclear power stations. I hope our experience will be a good lesson to them.”

It reminded me of something that tsunami survivors mentioned in the first days after the waves receded. Up and down the battered coast, they had rediscovered gnarled stone tablets, some of them hundreds of years old, which had been left by ancient ancestors at precise points on the shore to indicate the high-water marks of previous tsunamis. The inscriptions implored future generations never to build closer to the water again. “No matter how many years may pass,” read one, “do not forget this warning.” ♦

Evan Osnos joined The New Yorker as a staff writer in 2008, and covers politics and foreign affairs.